The invention relates generally to a wavelength selective switch (WSS) array for use in optical communication networks. Optical networks are employed in order to support present day demand for high-speed, high-capacity advanced telecommunications and data networks. These networks commonly use a technique known as optical wavelength division multiplexing (WDM) to exploit as much of the optical spectrum as possible. Optical WDM is analogous to radio WDM in that data is modulated onto several different carrier waves of different wavelengths, with carriers at different wavelengths referred to as channels. In optical WDM, a light wave is used rather than a radio wave with the different wavelength channels corresponding to different frequencies (wavelengths) of light. Optical communications are commonly employed in and around a wavelength of 1-2 microns.
In many optical networks, optical nodes are employed that correspond to branch points of the optical network. Often, it is desirable for the nodes to employ Reconfigurable Optical Add Drop Multiplexer (ROADM) devices that have a reconfigurable add-drop functionality. Generally speaking, ROADM functionality allows for the removal or addition of one or more wavelength channels at the node.
In order to realize a ROADM system, a WSS may be employed for the routing of any arbitrary wavelength channel. In a WSS, a light beam deflection device such as a spatial light modulator may be used to select a wavelength for deflection to a desired output port, e.g., deflection of a wavelength channel to a drop port will result in that channel being dropped from the WDM signal. Furthermore, WSS's that employ MEMS (Micro-Electro-Mechanical System) or LCOS (Liquid Crystal on Silicon) based spatial light modulators are also currently in use.
Conventionally, ROADM nodes employ the Broadcast and Select (BS) scheme that requires a WSS and an optical splitter. However, future devices may employ route and select (RS) schemes that employ multiple WSS devices without the use of the optical splitter.